1. Field of the Invention
This invention relates to automatic programming equipment and, more particularly, to such equipment and systems providing accurate control of multiple devices in, for example, an entertainment or educational system utilizing multi-media techniques.
2. Description of the Prior Art
In presenting a program for education or entertainment which involves the use of both audio and visual devices and effects, for example in presenting a program in a planetarium, it is a very difficult task to assure that the audible and visible effects are produced at the right instant and in the right relationship. In planetaria, for example, the lecturer is frequently charged with the task of not only presenting the description of what is being seen and heard but also must control the numerous slide projectors, star image projectors and other audio-visual equipment associated with his presentation. There has been an attempt to automate the control of the audio-visual effects, one of the most common approaches being to use punched paper tape and a reader for that tape. Such punched paper tape systems are limited in the functions they can perform for, essentially, they can only initiate an on-off action, for example a switch closure. That switch closure may then control a dissolve unit which has a pre-set fade rate to make an electric lamp fade from zero lamp level to full light level and, at an alternate command, to fade from the full light level to zero light level. Such a paper tape system may also control a slide projector. For example, at any time the light fades from full on to off the slide changer may be activated automatically. Many other programmers on the market today are essentially variations of this paper tape reading system. Some use tone encoded magnetic tape, and some use digital address codes on tape, but, again, they only control on-off functions. These programmers of the prior art cannot program a wide range of light levels for a single device.
There have been some programmers on the market that use magnetically recorded analog information, such as varying frequency, to, in turn, effect proportional light level variations. These systems require one recording channel for each device to be proportionally controlled.
Other prior art systems have used dual-gap heads or dual tracks to record digital control information. With either of these systems the making of a correction requires playing the tape from beginning to end. If corrections are made at random, gaps result causing intolerable interference in the system.
Accordingly, it is a general object of the present invention to provide improved equipment which permits multimedia programming utilizing a single magnetic recording track.
It is a further object of the present invention to provide a multi-media programmer which permits changes in the recorded program at any point without requiring re-recording of the previously recorded control information which is not changed.
It is a still further object of the present invention to provide versatile, relatively low cost multi-media programming equipment with a wide range of control in the operation of the associated audio-visual devices and in which a program can be created, if desired, by a plurality of recording passes, similar to sound-on-sound recording in audio tape recorders.